Distribution Of Calbindin Research Articles

ИММУНОГИСТОХИМИЧЕСКОЕ ИССЛЕДОВАНИЕ КАЛЬБИНДИНАВ РАЗВИВАЮЩЕМСЯ МОЗЖЕЧКЕ КРЫСЫ

Background. Calbindin is a calcium-binding protein that supports calcium homeostasis for the normal functioning of neurons. Purpose. To study the distribution of immunoreactivity of calbindin-D28K in the structures of the developing cerebellum of the rat.Material and methods. The study was performed on 16 outbred white rats of different age groups: 2-, 7-, 15-days (early postnatal period), 45-days (puberty period). The cerebellum samples were taken and fixed in zinc-ethanol-formaldehyde for immunohistochemistry. Calbindin-D28K immunoreactivity was determined on paraffin sections using primary polyclonal rabbit antibodies.Results. In the cerebellar cortex, calbindin immunoreactivity was detected on the 2nd day after development of Purkinje cells (PC) in their perikaryons, and by the 15th day in their dendrites and it did not change by the 45th day. In all terms of the study in PC, it was detected not only in the cytoplasm, but also in their nucleus. In the granular layer, calbindin immunoreactivity decreased in rats in postnatal ontogenesis, however, in adult rats, some neurons were moderately immunopositive. Among them, from the 15th day after birth, the calbindin-immunoreactive afferent nerve fibers running in the white matter were detected. There were no significant differences in the distribution of calbindin between the lobes of the cerebellum of different phylogenetic age. Conclusions. Considering that the expression of сalbindin-D28k is detected throughout the entire period of development of Purkinje cells, as well as its physiological role in maintaining the function and homeostasis of calcium in them, it can be concluded that сalbindin-D28k is a valuable marker for the morphofunctional characteristics of PC in the developing and adult cerebellum of rats in normal and pathological conditions.

Regional chemoarchitecture of the brain of lungfishes based on calbindin D-28K and calretinin immunohistochemistry.

Lungfishes are the closest living relatives of land vertebrates, and their neuroanatomical organization is particularly relevant for deducing the neural traits that have been conserved, modified, or lost with the transition from fishes to land vertebrates. The immunohistochemical localization of calbindin (CB) and calretinin (CR) provides a powerful method for discerning segregated neuronal populations, fiber tracts, and neuropils and is here applied to the brains of Neoceratodus and Protopterus, representing the two extant orders of lungfishes. The results showed abundant cells containing these proteins in pallial and subpallial telencephalic regions, with particular distinct distribution in the basal ganglia, amygdaloid complex, and septum. Similarly, the distribution of CB and CR containing cells supports the division of the hypothalamus of lungfishes into neuromeric regions, as in tetrapods. The dense concentrations of CB and CR positive cells and fibers highlight the extent of the thalamus. As in other vertebrates, the optic tectum is characterized by numerous CB positive cells and fibers and smaller numbers of CR cells. The so-called cerebellar nucleus contains abundant CB and CR cells with long ascending axons, which raises the possibility that it could be homologized to the secondary gustatory nucleus of other vertebrates. The corpus of the cerebellum is devoid of CB and CR and cells positive for both proteins are found in the cerebellar auricles and the octavolateralis nuclei. Comparison with other vertebrates reveals that lungfishes share most of their features of calcium binding protein distribution with amphibians, particularly with salamanders.

Cocaine- and amphetamine–regulated transcript peptide and calcium binding proteins immunoreactivity in the deep layers of the superior colliculus of the guinea pig: Implications for multisensory and visuomotor processing

The superior colliculus (SC) of mammals is a midbrain center, that can be subdivided into the superficial (SCs) and deep layers (SCd). In contrast to the visual SCs, the SCd are involved in multisensory and motor processing. This study investigated the pattern of distribution and colocalization of cocaine- and amphetamine-regulated transcript peptide (CART) and three calcium-binding proteins (CaBPs) i.e. calbindin (CB), calretinin (CR) and parvalbumin (PV) in the SCd of the guinea pig. CART labeling was seen almost exclusively in the neuropil and fibers, which differed in regard to morphology and location. CART-positive neurons were very rare and restricted to a narrow area of the SCd. The most intense CART immunoreactivity was observed in the most dorsally located sublayer of the SCd, which is anatomically and functionally connected with the SCs. CART immunoreactivity in the remaining SCd was less intensive, but still relatively high. This characteristic pattern of immunoreactivity indicates that CART as a putative neurotransmitter or neuromodulator may play an important role in processing of visual information, while its involvement in the auditory and visuomotor processing is less significant, but still possible. CaBPs-positive neurons were morphologically diverse and widely distributed throughout all SCd. From studied CaBPs, CR showed a markedly different distribution compared to CB and PV. Overall, the patterns of distribution of CB and PV were similar in the entire SCd. Consequently, the complementarity of these patterns in the guinea pig was very weak. Double immunostaining revealed that CART did not colocalize with either CaBPs, which suggested that these neurochemical substances might not coexist in the multisensory and visuomotor parts of the SC.

Calcium binding protein expression in the optic tectum of Alligator during development

The onset and distribution of the calcium binding proteins, calretinin, calbindin, and parvalbumin, were examined in the optic tectum of Alligator mississipiensis embryos between Stages 18 and 26-28. The immunoreactivity of each calcium binding protein correlated well with the results from the Western blot experiments. In terms of onset and distribution, calretinin expressison was the most widespread of the three calcium binding proteins that were examined, and was also the earliest to be visualized. Calbindin expression occurred next, whereas parvalbumin expression was the most limited and appeared last. For small calretinin (+) neurons, the pattern of immunoreactivity during development was from inside to outside, whereas for the larger cells, it was from outside to inside. For calbindin immunoreactive cells in the superficial zone, the pattern was from outside to inside. The distribution of the parvalbumin immunopositive neurons did not change significantly over the time period examined. Similar data on other amniotes is limited. However, the pattern in Alligator shares some similarities with kittens in regards to the distribution of calbindin and parvalbumin in the developing superior colliculus.

Glutamatergic projection from the nucleus incertus to the septohippocampal system

Recent findings support a relevant role of the nucleus incertus in the control of the hippocampal activity through the modulation of theta rhythm. Previous studies from our group have shown that this nucleus is a critical relay between reticularis pontis oralis and the medial septum/diagonal band, regarded as the main activator and the pacemaker of the hippocampal oscillations, respectively. Besides, the nucleus incertus is highly linked to activated states related to the arousal response.The neurotransmission of the nucleus incertus, however, remains uncertain. Only GABA and the neuromodulator relaxin 3 are usually considered to be involved in its contribution to the septohippocampal system. In this work, we have analyzed the existence of an excitatory projection from the nucleus incertus to the medial septum. We have found a group of glutamatergic neurons in the nucleus incertus projecting to the medial septum. Moreover, we were able to describe a segregated distribution of calbindin and calretinin neurons. While calretinin expression was restricted to the nucleus incertus pars compacta, calbindin positive neurons where observed both in the pars dissipata and the pars compacta of the nucleus.The present work provides innovative data supporting an excitatory component in the pontoseptal pathway.

Chronic 835-MHz radiofrequency exposure to mice hippocampus alters the distribution of calbindin and GFAP immunoreactivity

Exponential interindividual handling in wireless communication system has raised possible doubts in the biological aspects of radiofrequency (RF) exposure on human brain owing to its close proximity to the mobile phone. In the nervous system, calcium (Ca 2+) plays a critical role in releasing neurotransmitters, generating action potential and membrane integrity. Alterations in intracellular Ca 2+ concentration trigger aberrant synaptic action or cause neuronal apoptosis, which may exert an influence on the cellular pathology for learning and memory in the hippocampus. Calcium binding proteins like calbindin D28-K (CB) is responsible for the maintaining and controlling Ca 2+ homeostasis. Therefore, in the present study, we investigated the effect of RF exposure on rat hippocampus at 835 MHz with low energy (specific absorption rate: SAR = 1.6 W/kg) for 3 months by using both CB and glial fibrillary acidic protein (GFAP) specific antibodies by immunohistochemical method. Decrease in CB immunoreactivity (IR) was noted in exposed (E1.6) group with loss of interneurons and pyramidal cells in CA1 area and loss of granule cells. Also, an overall increase in GFAP IR was observed in the hippocampus of E1.6. By TUNEL assay, apoptotic cells were detected in the CA1, CA3 areas and dentate gyrus of hippocampus, which reflects that chronic RF exposure may affect the cell viability. In addition, the increase of GFAP IR due to RF exposure could be well suited with the feature of reactive astrocytosis, which is an abnormal increase in the number of astrocytes due to the loss of nearby neurons. Chronic RF exposure to the rat brain suggested that the decrease of CB IR accompanying apoptosis and increase of GFAP IR might be morphological parameters in the hippocampus damages.

Activity-Dependent Codevelopment of the Corticospinal System and Target Interneurons in the Cervical Spinal Cord

Corticospinal tract (CST) connections to spinal interneurons are conserved across species. We identified spinal interneuronal populations targeted by the CST in the cervical enlargement of the cat during development. We focused on the periods before and after laminar refinement of the CST terminations, between weeks 5 and 7. We used immunohistochemistry of choline acetyltransferase (ChAT), calbindin, calretinin, and parvalbumin to mark interneurons. We first compared interneuron marker distribution before and after CST refinement. ChAT interneurons increased, while calbindin interneurons decreased during this period. No significant changes were noted in parvalbumin and calretinin. We next used anterograde labeling to determine whether the CST targets different interneuron populations before and after the refinement period. Before refinement, the CST terminated sparsely where calbindin interneurons were located and spared ChAT interneurons. After refinement, the CST no longer terminated in calbindin-expressing areas but did so where ChAT interneurons were located. Remarkably, early CST terminations were dense where ChAT interneurons later increased in numbers. Finally, we determined whether corticospinal system activity was necessary for the ChAT and calbindin changes. We unilaterally inactivated M1 between weeks 5 and 7 by muscimol infusion. Inactivation resulted in a distribution of calbindin and ChAT in spinal gray matter regions where the CST terminates that resembled the immature more than mature pattern. Our results show that the CST plays a crucial role in restructuring spinal motor circuits during development, possibly through trophic support, and provide strong evidence for the importance of connections with key spinal interneuron populations in development of motor control functions.

Sex Differences and the Development of the Rabbit Brain: Effects of Vinclozolin1

The preoptic/anterior hypothalamic area (POA/AH) is one of the most sexually dimorphic areas of the vertebrate brain and plays a pivotal role in regulating male sexual behavior. Vinclozolin is a fungicide thought to be an environmental antiandrogen, which disrupts masculine sexual behavior when administered to rabbits during development. In this study, we examined several characteristics of the rabbit POA/AH for sexual dimorphism and endocrine disruption by vinclozolin. Pregnant rabbits were dosed orally with vinclozolin (10 mg/kg body weight) or carrot paste vehicle once daily for 6 wk beginning at midgestation and continuing through nursing until Postpartum Week 4. At 6 wk, offspring were perfused with 4% paraformaldehyde and brains processed for immunocytochemical localization of tyrosine hydroxylase, calbindin, gonadotropin-releasing hormone (GnRH), or Nissl stain. There were significant sex differences in the distribution of calbindin in the POA/AH and the size of cells in the dorsal POA/AH (values greater in females than in males), but not in the number or distribution of tyrosine hydroxylase or GnRH neurons. In both sexes, exposure to vinclozolin significantly increased calbindin expression in the ventral POA/AH and significantly decreased number of GnRH neurons selectively in the region of the organum vasculosum of the lamina terminalis (OVLT) but not more caudally in the POA/AH. This is the first documentation of a sexually dimorphic region in the rabbit brain, and further supports the use of this species as a model for studying the influence of vinclozolin on reproductive development with potential application to human systems.

Postnatal Developmental Expression of Calbindin, Calretinin and Parvalbumin in Mouse Main Olfactory Bulb

The distribution of calbindin, calretinin and parvalbumin during the development of the mouse main olfactory bulb (MOB) was studied using immunohistochemistry techniques. The results are as follows: (1) calbindin-immunoreactive profiles were mainly located in the glomerular layer, and few large calbindin-immunoreactive cells were found in the subependymal layer of postnatal day 10 (P10) to postnatal day 40 (P40) mice; (2) no calbindin was detected in the mitral cell layer at any stage; (3) calretinin-immunoreactive profiles were present in all layers of the main olfactory bulb at all stages, especially in the olfactory nerve layer, glomerular layer and granule cell layer; (4) parvalbumin-immunoreactive profiles were mainly located in the external plexiform layer (except for P10 mice); (5) weakly stained parvalbumin-immunoreactive profiles were present in the glomerular layer at all stages; and (6) no parvalbumin was detected in the mitral cell layer at any stage.

Calbindin, Calretinin and Parvalbumin Immunoreactivity in the Retina of the Chameleon (Chamaeleo chamaeleon)

Apart from the pioneering studies of Ramon y Cajal [1893] and Rochon-Duvigneaud [1943], few studies have been devoted to the detailed study of the cytological and biochemical structure of the chameleon retina. In the present study we analyzed the expression of calbindin (CB), calretinin (CR) and parvalbumin (PV) immunoreactivities in the chameleon retina, and compared their distribution with those found in the retinas of other vertebrate species. CB immunoreactivity is dense in photoreceptors, horizontal and some lower amacrine cells. The most intense immunoreactivity was observed for calretinin; CR-ir amacrine cells are distributed throughout the inner nuclear, inner plexiform, and ganglion cell layers of the retina. Horizontal cells also display immunoreactivity to CR. A few retinal interneurons are weakly PV-ir. Double-labeling shows that all PV-ir or CB-ir cells, except the photoreceptors, are also strongly CR-ir. The distributions of these calcium-binding proteins in the chameleon retina share similarities with those observed in mammalian and avian retinas. In addition, the widespread distribution and co-localization of CB and CR reinforces the idea that these proteins play a general role in buffering the intracellular calcium levels in retinal cells. Furthermore, CB- and CR-immunoreactivities have enabled us to identify for the first time axon-bearing horizontal cells in the peripheral retina of the chameleon, very similar to those described in mammals.

Calbindin distribution in male, female and lactating rat pituitary

Calcium binding proteins such as calbindin and calretinin have been studied in the pituitary gland, but information on them is still incomplete. To investigate the localization, distribution and role of calbindin in the pituitary, several antibodies to calbindin and to other pituitary markers, such as calretinin and tyrosine–hydroxylase, have been used in male, female and lactating rats. Calbindin has not been localised to a specific endocrine cell population unlike calretinin in the thyrotrophs. There was occasional localization in somatotrophs, thyrotrophs and luteotrophs, but not in corticotrophs or lactotrophs. However, there are sex differences in the expression of this protein as the number of calbindin-immunoreactive cells is higher in the male than in the female pituitary. Furthermore, the number of calbindin containing cells, not lactotrophs, increases in lactating rats and decreases after removal of the pups. It is concluded that calbindin expression may be altered by physiological and endocrine events such lactation, even though it is still unclear why the protein is not related to a specific cell type. The simultaneous use of monoclonal and polyclonal antisera to calbindin revealed that the rabbit antibody recognizes nuclear and cytoplasmic calbindin, while the monoclonal one binds only to the cytoplasmic calbindin. The suggestion is that calbindin may have a secondary role that is not simply to bind calcium.

Functional and structural analysis of the visual system in the rhesus monkey model of optic nerve head ischemia.

A redistribution of neurochemicals has been identified in the visual cortex of monkeys with laser-induced glaucoma. Examined were functional, structural, and neurochemical changes to the retina, optic nerve, and central visual system in a nonhuman primate model of optic nerve head (ONH) ischemia caused by sustained unilateral administration of endothelin (ET)-1 to the optic nerve. ET-1 or sham control solution was delivered by osmotic minipump to the retrolaminar region of one optic nerve of rhesus monkeys (Macaca mulatta) for 1.5 years. ONH topography and blood flow velocity were serially studied with scanning laser tomography and laser Doppler flowmetry, respectively. Retinal and cortical electrophysiologic measurements from pattern-derived stimuli were obtained quarterly. Immunohistochemistry was used to identify the distribution of calbindin (CB) and c-Fos labeled neurons in the visual cortex areas V1 and V2, and lateral geniculate nucleus (LGN). Retinal ganglion cell counts and optic nerve axon density were determined by light microscopy. No significant changes in retinal and ONH morphology, ONH blood flow velocity, and retinal and cortical pattern-derived functional activity were detected. Measurement of CB-positive cell density in V1 and V2 showed a significant decrease in CB labeling to the contralateral side of the ET-1-treated eye (P < 0.04). CB-positive cells were present in the magnocellular layers of the LGN with no differences noticed between the ET-1- and sham-treated eyes. c-Fos-labeled neurons were found in striate area V1 and extrastriateV2 of both groups. No c-Fos labeling was observed in the LGN. Administering ET-1 to the orbital optic nerve alters neuronal metabolic activity in the visual cortex in rhesus monkeys. Metabolic activity reductions in the visual cortex precede the ability to detect functional and structural alterations in the retina, ONH, and visual cortex in this animal model.

Cortical Orofacial Motor Representation in Old World Monkeys, Great Apes, and Humans

This study presents a comparative stereologic investigation of neurofilament protein- and calcium-binding protein-immunoreactive neurons within the region of orofacial representation of primary motor cortex (Brodmann’s area 4) in several catarrhine primate species (Macaca fascicularis, Papio anubis, Pongo pygmaeus, Gorilla gorilla, Pan troglodytes, and Homo sapiens). Results showed that the density of interneurons involved in vertical interlaminar processing (i.e., calbindin- and calretinin-immunoreactive neurons) as well pyramidal neurons that supply heavily-myelinated projections (i.e., neurofilament protein-immunoreactive neurons) are correlated with overall neuronal density, whereas interneurons making transcolumnar connections (i.e., parvalbumin-immunoreactive neurons) do not exhibit such a relationship. These results suggest that differential scaling rules apply to different neuronal subtypes depending on their functional role in cortical circuitry. For example, cortical columns across catarrhine species appear to involve a similar conserved network of intracolumnar inhibitory interconnections, as represented by the distribution of calbindin- and calretinin-immunoreactive neurons. The subpopulation of horizontally-oriented wide-arbor interneurons, on the other hand, increases in density relative to other interneuron subpopulations in large brains. Due to these scaling trends, the region of orofacial representation of primary motor cortex in great apes and humans is characterized by a greater proportion of neurons enriched in neurofilament protein and parvalbumin compared to the Old World monkeys examined. These modifications might contribute to the voluntary dexterous control of orofacial muscles in great ape and human communication.

Characterization of calbindin-positive cones in primates

The aim of this study is to characterize calbindin-positive photoreceptors and their opsin content in the retina of nocturnal prosimians ( Microcebus murinus), New World monkeys ( Callithrix jacchus), Old World monkeys ( Macaca fascicularis), and humans. To identify the calbindin and opsin content of cones, combined multiple labeling with different fluorescent probes, antibodies directed against calbindin, short, and mid–long wavelength opsins, and lectin peanut agglutinin cytochemistry were used. With the exception of Microcebus, calbindin is present in the cones of all primates but is absent from rods. The distribution of calbindin is similar in human and macaque cones, with dense label in the inner segment, cell body, axon and cone pedicle. Cones in marmoset also show dense staining in the cell body, axon and pedicle but only light label in the inner segment. Primate cone outer segments do not contain calbindin. In the primates studied, three patterns of calbindin and opsin localization are observed. In macaque and marmoset all short and mid–long wavelength cones contain calbindin. In humans, all mid–long wavelength cones contain calbindin whereas all short wavelength cones are devoid of calbindin as confirmed by confocal microscopy. In the nocturnal prosimian Microcebus none of the mid–long or short wavelength cones contain calbindin. In addition to primates, calbindin is absent in cones of other nocturnal species but is present in cones of diurnal species suggesting a difference in the role of calbindin possibly related to the adaptational states or other photoreceptor properties.

Distribution of calbindin D-28k in the entorhinal, perirhinal, and parahippocampal cortices of the macaque monkey.

We examined the distribution of calbindin D-28k-immunoreactive (CB-IR) neurons, fibers, and neuropil in the entorhinal (area 28), perirhinal (areas 35 and 36), and parahippocampal (areas TH and TF) cortices in the macaque monkey. Two main findings are reported. First, except for CB-IR neurogliaform cells that are only observed in the parahippocampal cortex, the morphology of CB-stained pyramidal and nonpyramidal cells were similar across the three cortical areas examined. Second, we find that the topography of CB staining differed between the three areas. The entorhinal cortex exhibits the most striking gradient of CB staining such that the most anterior and medial portions are most strongly labeled, whereas posterior and lateral areas exhibit only weak labeling. The labeling throughout the perirhinal and parahippocampal cortices is more homogeneous. Area 35 contains only lightly stained neuropil and few CB-IR cells. Area 36 and areas TH and TF of the parahippocampal cortex contain a moderate to high density of CB-IR cells and fibers throughout their full rostrocaudal extents, although each area exhibits unique laminar patterns of staining. In all areas examined, the highest density of CB-positive cells and fibers is observed in superficial layers with lower densities of CB-positive cells and fibers present in deep layers. These findings, taken together with our current understanding of the connections of these areas may have implications for understanding the circuit properties of the entorhinal, perirhinal, and parahippocampal cortices areas in both normal and disease states.

Calbindin and calretinin immunoreactivities in the retina of a chondrostean, Acipenser baeri.

The distribution of calbindin and calretinin in the retina of the sturgeon Acipenser baeri was studied with immunocytochemistry. Western blot analysis of brain extracts, together with immunocytochemical results in the retina and brain, indicated the presence of the two calcium-binding proteins in sturgeon. Calbindin immunocytochemistry revealed only a large displaced bipolar cell type with narrowly stratified axons, similar to some mixed rod and cones bipolar cells described in teleosts. The plexus formed by the axons of these cells in the inner plexiform sublayer was similar to that formed by calbindin-immunoreactive diffuse bipolar cells of some mammals. Calretinin immunocytochemistry also stained these displaced bipolar cells, most ganglion cells including displaced ganglion cells (Dogiel cells), and some amacrine cells of the inner nuclear layer. The distribution of calbindin and calretinin immunoreactivities in the retina of a primitive bony fish indicates that these proteins are highly specific to the cell type.

Organization of human hypothalamus in fetal development

The organization of the human hypothalamus was studied in 33 brains aged from 9 weeks of gestation (w.g.) to newborn, using immunohistochemistry for parvalbumin, calbindin, calretinin, neuropeptide Y, neurophysin, growth-associated protein (GAP)-43, synaptophysin, and the glycoconjugate 3-fucosyl- N-acetyl-lactosamine. Developmental stages are described in relation to obstetric trimesters. The first trimester (morphogenetic periods 9-10 w.g. and 11-14 w.g.) is characterized by differentiating structures of the lateral hypothalamic zone, which give rise to the lateral hypothalamus (LH) and posterior hypothalamus. The PeF differentiates at 18 w.g. from LH neurons, which remain anchored in the perifornical position, whereas most of the LH cells are displaced laterally. A transient supramamillary nucleus was apparent at 14 w.g. but not after 16 w.g. As the ventromedial nucleus differentiated at 13-16 w.g., three principal parts, the ventrolateral part, the dorsomedial part, and the shell, were revealed by distribution of calbindin, calretinin, and GAP43 immunoreactivity. The second trimester (morphogenetic periods 15-17 w.g., 18-23 w.g., and 24-33 w.g.) is characterized by differentiation of the hypothalamic core, in which calbindin- positive neurons revealed the medial preoptic nucleus at 16 w.g. abutted laterally by the intermediate nucleus. The dorsomedial nucleus was clearly defined at 10 w.g. and consisted of compact and diffuse parts, an organization that was lost after 15 w.g. Differentiation of the medial mamillary body into lateral and medial was seen at 13-16 w.g. Late second trimester was marked by differentiation of periventricular zone structures, including suprachiasmatic, arcuate, and paraventricular nuclei. The subnuclear differentiation of these nuclei extends into the third trimester. The use of chemoarchitecture in the human fetus permitted the identification of interspecies nuclei homologies, which otherwise remain concealed in the cytoarchitecture.

Distribution of Calbindin Immunostained Neurons in the Rat Substantia Nigra

Distribution of Calbindin Immunostained Neurons in the Rat Substantia Nigra

Onset of calbindin-D 28K and parvalbumin expression in the lateral geniculate complex and olivary pretectal nucleus during postnatal development of the rat

The onset and distribution of calbindin (CB) and parvalbumin (PV) immunoreactivity were investigated in the lateral geniculate nuclear complex and the olivary pretectal nucleus (OPT) in developing rats. CB expression occurred early (before eye-opening) in the relay neurons of the intergeniculate leaflet, parvocellular portion of the ventral lateral geniculate nucleus and OPT relating to ambient vision mediated by W-like retinal ganglion cells. On the contrary, PV expression occurred late (after eye-opening) in the relay neurons of the magnocellular portion of the ventral lateral geniculate nucleus (VLGMC) and OPT relating to focal vision mediated by Y-like retinal ganglion cells. A unilateral eye enucleating experiment indicated that the VLGMC and OPT received dense input from PV-positive Y-like retinal ganglion cells. The results show the different onsets of CB and PV expressions in the retino-recipient thalamic and pretectal nuclei receiving inputs from different kinds of retinal ganglion cells.

Calcification processes in the chick otoconia and calcium binding proteins: patterns of tetracycline incorporation and calbindin-D28K distribution

In order to clarify the otoconia formation and turnover, tetracycline, an antibiotic that precipitates at calcifying fronts and serves as a fluorescent marker, was injected into eggs at different stages of chick embryonic development, as well as into postnatal chicken and into adult animals. The changes in the intensity, location patterns and time course of fluorescent labelling in each examined stage in the otolithic organs was studied. The presence and distribution of calbindin (CB)-D28K, one of the calcium-binding proteins constantly found in the mammalian and chicken cochlea and also in otolithic membrane of some adult mammals, was studied. Results in embryonal stages, postnatal and adult animals allow us to postulate that otoliths are mainly produced during the embryonal phase, but they may also be produced throughout the whole life span. Results also indicate that otoconia are dynamic structures which undergo turnover. The correspondence between the patterns of CB-D28K immunoreactivity and tetracycline fluorescence may indicate that CB-D28K participates in the formation of otoconia.